Gather your tools before starting the overhauling process. You must find the appropriate sized cone wrench for your bike and an adjustable wrench as well.
Take out the wheel of your bike at first. Use the adjustable wrench to open up the bolts and remove the axle to take out the wheel of your bike.
Then, remove the nuts and washers which bound the bike to the frame. Modern day bikes have skewer instead of nuts and you will need to remove it instead.
If your bike has a rubber seal (like many Shimano bikes have) remove it as well.
Now take the cone wrench and place it on the wrench flat of the bike’s hub. At the same time, you have to place an adjustable wrench on the lock nut. Hold the cone wrench tightly and loosen up the lock nut with your other hand.
Unbolt the locknut, spacers and the cone before you move on to the next step.
The axle will be free to remove and you can easily pull it out with your fingers but make sure not to let the bearings fall out in the process.
Carefully take out the bearings from the hub and put them aside for a while.
Take a screwdriver and carefully remove the plastic seals on either sides of the bike’s hub. These seals might get brittle over time and you better not break them while removing.
Use a clean piece of cloth to clean out the hub thoroughly. If you see the bearing surface deeply pitted, it is time for you to replace the entire hub. Same is the case with the cones.
You can clean out the bearings in a jar or if you feel necessary, replace them with the new ones.
Apply some grease to the bearing races of the hub and replace the plastic seals.
Perform the steps in reverse order to reassemble the bike and that is it.